I'm having trouble tuning the overrun portion of my VE map. Mostly the AFR reads lean under overrun conditions from 6000 rpm down to about 2000. I say mostly because it tends to oscillate between lean and extremely lean. If I run VE analyse, it bumps some of these cells up to 140 where the next cells up are all between 70-80. These hugely rich VE values seem to help, but the AFR still jumps up from time to time.

The engine is burping and backfiring during this overrun so I don't really trust the AFR numbers. I've tried different ignition timing values in this area from 30 degrees to 60 degrees. It doesn't seem to matter. It seems as if the mixture just isn't combusting under these conditions. I really want to get all of the table dialed in so I can run EAE. I'll eventually switch to overrun fuel cut.

I think you're right. I think the injector opening time is too small. It gets down to 1.43 ms during over run.

I've done my best to tune the opening time by switching from 2 squirts/cycle to 4 and back and fourth. I shoot for the same idle AFR with EGO correction off of course. So I'm pretty confident in my opening time.

Just because I was tuning that portion of the table. Also, I've had it on before, but had problems entering idle way too lean. I think this will not be an issue once I tune and enable EAE since MS will know that the fuel puddle has evaporated during the fuel cut / overrun event.

I have also run in to the same problem as "16vboost" that the AFR jumps lean when in overrun area even when overrun cut turned off. As I too now started to tune my EAE curves.As you can see in the log capture the AFR behaves as the overrun fuel cut would be on even when it's not.It might be because PW gets too low to 1.2ms and at idling it is 1.7ms. Injector dead time is 0.55ms calculated with flow testing "Deka 630cc"

log_ve_table.bmp

But will this affect my EAE tuning? I will use overruncut anyway when I'm done with the EAE curves.

And another question to the EAE tuning, perhaps a silly one.There are instruction on how to tune the EAE. Keeping the rpm steady and chaning the kpa example from 40 to 80 and change the curve EAE curves depending on the result. But whitch point of the curve, the 40 kpa point or the 80 kpa or something else?

I'm using Jean's P&H-board to controll the injectors so my testings gave me a bit different value for the dead time.But I don't have any problems with the idle AFR because my normal idle has PW of 1.7 and it's on the linear zone.